Hello Guys. I was wondering what are the differences between 46 trim and 57 trim turbos. Im looking forward in putting a k26/t04e in my UrS4 and I was leaning toward the 46 trim. Only 21 max boost is needed for 400hp and all the dots are inside the compressor flow map including the FMIC and there is good spool up. Tell me your thoughts on this. I used http://www.turbofast.com.au/turbomap.html to calculate this. Here is a picture of the flow map:
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If you compare the maps you can see surge line is about the same (almost coincident) as the 57 trim, while max boost capabilityes are 0.3 bar less and flow around 60-70 lb/min.
This means you still will not be able to spool up the compressor earlyer in the rpm (given the hot side can) than the 57 trim.
Compared to the KKK K24-7200 (RS2) 46 trim looks to me it can deliver max boost at least 700-800 rpm higher in the rpm.
For maybe only 20 hp more, I think the KKK (RS2 type) is much better.
If you go for a T3/TO4e hybrid configuration go at least with the 57 trim, which will provide, with the right hot side wheel, up to 450-460 hp if needed.
Just my opinion
Marco -
Hi,
just to add to Marcos comments, I am running the 57 trim compressor and whilst I cant comment on the 46 trim or make comparisons between the two, I can tell you how mine performs.
Full spec is:
Turbonetics T3/TO4e hybrid
57 trim compressor
stage 3 turbine, 63mm exducer
Turbonetics copy of K26 #8 hot side housing, re worked to take the above turbine
ceramic ball bearing option
On a good day, I have to say that I am very happy so far with the unit and the way it performs, I get 1 bar at 3k rpm and from then on an almighty shove in the back as boost rapidly climbs and the wheels take turns to lose traction.
I am looking forwards to fitting a set of Carrillos in the near future so that Mihnea can really exploit the capabilites of the turbo and we can delve into the realms of mind altering torque, and not worry too much about breaking something
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Spool up is quick, considering the large size of the exducer, and is a lot down to the ceramic bearings (and possibly the MTM S1 ex man), but although I love the way I can get boost without waiting around for too long I can't yet say how reliable the ceramic bearings are or how long they will last, Ive heard different things from different people.
Choosing a turbo is hard (for me anyway) and the last thing I wanted was to end up with a donkey with excessive lag or something that would run out of puff over 400 bhp.
I took advice on the compressor trim from a couple of people in the states that post regularly over on 20V Kruemmer one of whom was using the 57 trim and recomended using it. I chose the turbine size after talking with my supplier/agent and took a chance with the larger turbine.
I am quite pleased with the choice I made and was quite lucky considering how little I know about these things and I suppose that the only time I can forsee me wanting to change things (barring any failures) will be that happy day, all being well, when I have my planned superdooper block/engine running, and the 450 bhp or so that the 57 trim is capable of.........is not enough
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Hope this helps a bit.
Cheers,
Mark.Mark - ModdedComment
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Thanks for the information guys. With 57 trim should I go with #6 or 8 housing? It will be a daily driver so I wont want a lot of lag. What are the RPM's that the #6 spools up on?
TonyComment
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Tony, I think without having the turbine maps for the #6 and #8 impellers, it is quite difficult to say which of the two would be better for your application.
But I feel I can say the #6 will not provide enaugh power at mid to high rpm to drive 57trim cold side at it's max flow and boost capabilityes.
If you plan not to go over the 380-400 hp output I would suggest you choose a different (smaller) cold side which will have sensibly lower surge line thus being able to be spooled up earlyer in the rpm, togheter with the #6 turbine. Ask the company who sells those turbochargers, maybe they can provide a 46 trim with modified impeller which will have a nicer surge line that the standard one.
MarcoComment
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Marco,
If Tony is not running on custom exhaust manifold (420-430hp max), I think the 46 trim or 50 trim are better options.
So, if the objective is 400hp peak with a good middle range torque the 46 trim will give this. I think that this turbo could give almost 430hp with a surge line on par with a peak of 1.8bar at 4100-4200rpm. If he will use continuos power (like driving top speed for a while, or track day use), I think the 50 trim will give more efficiency at peak power, but with a little more lag (1.8bar at 4500rpm).
The 57 trim will give him a worst surge line (at 4000rpm he can’t go more than 1,5bar due to the slope of the surge line) and the it has not the flow capability of the 50 trim.
The super 50 trim is better yet. It has a “more upward†characteristic (greater pressure and sloppier surge line - like the 7200 KKK) but with much more flow capability.
With that site that Tony posted is very easy to see different compressors for same points. It haven’t the super 50, but its very useful like a quickly guide.
Marco, I discovered that Turbonetics’s trim is not related with the size of the compressor rotor. It is related more with behavior between boost and flow for a given housing. It is calculated by (Inducer^2/Exducer^2 )*100.
Ok, all those things are pure theory. I’m praying to my car be ok for test tonight. So we will have another setting to compare.Silver Audi RS2Comment
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